The present invention concerns a twin-wire former for a paper machine, in particular for rebuilding of existing fourdrinier wire parts. The twin-wire former comprises a lower wire and an upper wire, these wires being guided by guide rolls, by forming rolls, and by a web-forming member. The former comprises a first forming roll at which the lower wire which runs over the first forming roll together with the upper wire, defining a forming gap in connection with the first forming roll, into which a slice part of a headbox feeds a pulp suspension jet.
With respect to the prior art related to the present invention, reference is made to a twin-wire former marked by Valmet under the trademark SPEED-FORMER HHS, which is a gap former principally intended for rebuilding of existing fourdrinier wire parts. A first object of the present invention is to provide a new former concept principally for the same purposes as this SPEED-FORMER HHS.
A starting point of the present invention is a so-called gap former in which, in a gap area, a forming roll or cylinder or relatively large diameter is used.
With respect to further prior art most closely related to the present invention, reference is made to FI Patent Application No. 851035 (Beloit Corporation), corresponding to U.S. Pat. No. 4,209,360 as well as to U.S. Pat. No. 4,209,360 corresponding to SE Pat. No. 7800775-4 (AB Karlstads Mek. Verkstad). The objectives of the present invention are partially the same as those of U.S. Pat. No. 4,209,360.